Railway signaling system



J. 'BL GRIFFITHS 2,225,473

RAILWAY SIGNALING SYSTEM Filed Aug. 9, 1938 9 Sheets-Sheet 1 Dec. 17, 1940.

Dec.

J. B. GRlFFlTHs RAILWAY SIGNALING SYSTEM Filed Aug. 9.` 193e 9 Sheets-Sheet 2 6 251,/ g asm 11M/re ATTORN De@ 17, 1940 J. B. GRIFFrrl-ls 2,225,473

RAILWAY S IGNALING SYSTEM y INVENTOR J. a. m/rr/ ms FIG. 2B, BY #59W ATTORN EY De@ 17, 1940- J. B. GRlFFrrHs 2,225,473

aAInLwAY SIGNALING- SYSTEM Filed Aug. 9, 1958 9 Sheets-Sheet 4 marlI ma f 0pm INVENTOR Je. GR/FF/rf/s HG. 2v.J BY W ATTORN Dec. 17, 1940. 1 B GRlFFn-Hs 2,225,473

RAILWAY SIGNALING SYSTEM Filed Aug. 9, 195s 9 sheets-sheet s Ina/2r sfu/Irl [NDLR Plazo.` g v` BY I Dec. 17, 1940.

J. B. GRIFFITHS RAILWAY SIGNALING SYSTEM Filed Aug. 9. 1938 31e me 3720/? 777? aai/30701? ,soep/e 9 sheets-sheet f5 @www SYN mr/ mrl 2 e//zeum ATTO/RN EY RAILWAY SIGNALING SYSTEM Flaa. j 5W ATTORNEY Def 17. 1940q J. B. GRIFFm-ls 2,225,473

RAILWAY S IGNALING SYSTEM Filed Aug. 9, 1938 9 Sheets-Sheet 9 5 LNII ,/CR co2 P. ugr SCR ca 16:1 u zf/2/CR I==d 2122 Erm" hr M n lilllilllllllllh HEL-07m griff/24 man. BY

ATTORNEY Patented Dec. 17, 1940 UNITED STATES PATENT OFFICE RAILWAY SIGNALING SYSTEM Application August 9, 1938, Serial No. 223,838 In Great Britain August 10, 1937 6 Claims.

This invention relates to remote'control of railway signal and track systems.

Many cases arise in practice of a set of siding track or switch points and signals, for instance,

which are changed at infrequent intervals but for which a signal box is provided, the majority of the signalmans work being to act as a tandem repeater for messages between busy signal boxes on either side.

10 Considerable economies could be achieved in systems mainly provided with local control, if control of infrequently operated switch points and signals were placed in the hands of adjacent main signal boxes, and it is the main object of the invention to provide such facilities.

The main feature of the invention comprises a system for the remote control of railway signals and switch points comprising route setting equipment which is located adjacent the track equipment to be controlled which is of thev kindnormally directly responsive to the manual operation of route levers, keys or the like to control the setting of signals and switch points in accordance with the route to be set up and which incorporates electrical interlocking between routes, control panel equipment at a distant switch point comprising route levers, keys or the like the movements of which are not interlocked with one another in any way, a signal channel between the route setting equipment position and the distant switch point together with signal transmitting equipment at the distant switch point` controlled by the levers, keys or the like and signal receiving equipment at the. route setting equipment position arranged to be capable of setting up a unique condition corresponding to every route setting lever or like operation possible at the distant switch point whereby said signal receiving equipment is adapted to simulate panel equipment for control of the route setting equipment.

It is proposed to use control signals for instance, of theconstant total code type, each characteristie of a complete set of conditions to be set up at a remotely controlled set of signals and points.

The proper reception of aconstant total code signal-correct number of digits and correct total number of impulses-checks that no error has occurred in transmission.

The new set of conditions would be set up in response to a correctly received code and a simple signal would be sent back to inform the signalman that the code sent had been correctly received.

Preferably the route signal would be used to set a sequence or other switch controlling the signal and points circuits in the manner described in the copending application of J. B. Grifliths and A. Brown, Serial No. 209,198, filed May 21, 1938. An answering constant-total code signal could be returned to the control cabin on correct re- 5 ceipt of a setting signal, said answering signal being individual to the particular setting signal received. In this case, the setting up of the route at the controlled position would not take place until the signalman,`on receipt of the check code 10 signal, sent an operating signal.

This system may be used in conjunction with a centralized traine indicator system such as that described in British Patent specification No, 461,136, acceptedFebruary 10, 1937 which is ar- 15 ranged to test the position of all equipment on a length of track at frequent intervals and to change the setting of an indicator at the control cabin accordingly. The change in the setting of the signals and switch points in response to a 20 constant-total code setting signal would be indicated in a short time on the indicator board.

This system of remote control and indication, besides being applicable to the circumstances detailed above, is also capable of use for the remote 25 control of a number of spaced sets of switch points and signals in tandem, for instance, by using a preliminary constant-total code signal characteristic of the set to be controlled.

The invention will be clearly understood from 30 the following description of one embodiment thereof shown in the accompanying drawings, in which:

Fig. 1 shows schematically the equipment layout from the remote control and indication of a 35 change-over set of switch points and signals;

Figs. 2A and 2B taken together show the code transmission equipment at a signal cabin for remote control;

Figs. 2C and 2D show the code receiving equip- 40 ment adjacent the set of switch points and signals to be remotely controlled for use with the transmitter of Figs` 2A and 2B;

Figs. 3A and `SBshow the centralized traffic indicating equipment at the signal cabin; while 45 Figs. 3C and 3D show isolated and group way station equipments of. the centralized trame indicating system.

Fig. 1 shows a general diagram of the arrangement, illustrating at PSG the track layout for a 50 small interlocking area which is required to be controlled from a panel CPE in a remote signal cabin SC.

The control panel CPE incorporates a mimicv diagram of the track with route switches situated 55 at points in the diagram corresponding to the signals, individual point switches provided for the emergency control of the switch points, switch point detection indicators and track circuit indicators as described in the oopending application of J. B Griffiths and Andrew Brown, Serial No. 209,198.'

The control switches on the panel are not interlocked in any way and are free to move at any time. The operation of any control switch starts up code signal transmitting equipment STE which transmits a unique code (constant total, that is,

one in which the sum of the digits transmitted for any code is constant, is preferred) to a code signal receiving equipment SRE adjacent the points and signals to be controlled.

The receipt of this code will actuate sequence switch interlocking route setting equipment RSE to complete the desired control, provided that it is safe'to do so in respect of the routes already set up and local traffic conditions.

The sequence switch interlocking equipment RSE will be similar to that already described in Application Ser. No, 209,198 and route relays operated by the code receiver correspond to the panel route switches operated by the signalman.

Having effected the necessary switching by rei moteV control, in conjunction with local interlocking, it is still desirable to provide the signal man with a complete indication of the state of his track and traffic and it is proposed to accomplish this over a separate communication channel by means of a centralized traflic indication system similar to that described in British Patent No.

' For the purposes of this description it is assumed that the track between the signal cabin and track section PSG is controlled by automatic signaling, in which case it is only necessary to indicate to the signal man the occupation of the various track sections thereof, a way-station WS Y units for each device to be indicated, and conlto siderable economy is effected by providing a group way station GWS for this equipment. 'I'he way stations are connected by a signal channel to indicator equipment IE in the signal cabin SC.

A more complete understanding of the system may be had by consideration of the wiring diagram of the circuits of CPE, STE, SRE and RSE shown in detail in Figs. 2A, 2B, 2C and 2D, these figures being arranged in a line with their vertical dimensions adjacent each other. In these diagrams the relays are shown in solid lines and the contacts are not all shown directly adjacent the controlling relays because of the complexity of'the circuit. To facilitate understanding, the relays are shown in light dotted lines adjacent each of the contacts which they control.

The cams of the sequence switchesare shown by the usual convention, those associated with switch S being designated SA, SB, SC, etc., and those associated with switch T being designated ITA, TB, TC, etc. Switches S and T are of well known construction and are indicated only by the conventional schematic illustration of sequence switches. Thevbrushes making continuouspermanent contact with the cams are shown directly connected thereto, those contacting only at discreet positions are designated by numerals l, 2, 3, 4, etc., see cam SG, Fig. 2A, those making continuous contact between certain positions being designated 1/2, see cam SP, Fig. 2B, and those making contact at every position but not continuous therebetween being designated I-I, see cam SA, Fig. 2B. The designation e. g. 1%/2 cam SB, Fig. 2A, indicates that contact is made at position [3/1, just a little in advance of position 2, so that the switch may be brought to a stop in position 2. The usual positioning cam on the sequence switch serving to properly center the contacts.

The panel equipment CPE is provided with a manual key for each route, 2| RK-30 RK, Fig. 2A, each key having normal and reverse positions, and a channel key for each track point each having normal, neutral and reverse positions and each indicated, e. g. by BIPKN and SIPKR, Fig. 2A.

To set up a route one of the signal keys is p operated and starts a Searcher-switch into operation to test the proposed route setting. This switch then stops in its chosen setting a further code switching arrangement is energized and transmits from STE signal impulses corresponding to the signal or switch point setting desired.

This code is received at the signal receiver SRE at which point is provided means responsive to the code sent. If the code is properly received a circuit is completed for transmitting back to the sending end a check signal to this effect, and then operate the route setting equipment to se up the chosen route. y

If the code is not properly received a signal indicating the error is transmitted back to the control panel. The operator may then try again to set up the route if desired after operating a fault clearing switch to clear faults which may exist in the circuit.

In order that conflicting routes may not be set up the transmitter is provided with a set of sequence switches and interlock circuits so that code signals will not be sent to the receiver unless the track is clear. By sending a route breakdown signal the routes previously set up may be reset to the original condition when desired.

As a further check on the operation of the system an arrangement is provided operated by the switch points and signals for indicating at the signal cabin on equipment IE the condition .of the tracks and signals.

At the signal cabin is provided a distributor arrangement continuously driven by a motor or some other means. This distributor sends out positive or negative impulses which pass successively through any stations in the track circuit, such as way stations WS and group way stations GWS. The number of impulses from the distributor correspond to the stations to be checked. Upon receipt of the signal, for example at the first way station, an indication of clear or occupied, is given depending on the condition of the corresponding track section at the time. At the way station relays are arranged to complete a circuit through to the next station so that the succeeding impulse is received at the next station and so on through the entire track system under control of the signal cabin. In dependance on the condition of the track sections as indicated, signal lamps are lighted at the equipment IE so that the signalman is continuously apprised of the track condition. ,A complete description of the operation follows considering particularly ex- Cil amples of route setting signals and operation of the system.

Considerv the case of a signalman attempting to set up route No. 2 I, by operating key 2IRK.

The signalman operates the panel control switch ZIRK to its reverse (lower) position, thereby completing a circuit from positive, contacts ZIRK, 2IlrI, resistance 2IYA, winding of relay SS to negative operating relay SS.

Operation of SS energizes the Searcher switch clutch. magnet SM (Fig. 2B) from positive, contacts st3, ssI, cam TC (when the transmitting switch T is in its home position), clutch magnet SM, relay MS to negative operating SM and MS.

Contacts msIy and m52 closed by MS start up the common moto-r M for all sequence switch drives from a current source AC and the searcher switch S will rotate as long as the above circuit persists. Wherever the Searcher switch started it revolves into position I, whereupon a circuit is completed for the relay ST (Fig. 2A) from positive, contacts ZIRK, 2Ilrl, cam SB in position I, winding of relay ST to negative, causing ST to operate and close its contacts.

The contacts st3 (Fig. 2B) interrupt the circuit for the Searcher switch clutch magnet SM, thus stopping the searcher switch in position I, corresponding to the panel switch 2IRK just operated. Relay ST remains locked over contacts stl (Fig. 2A) and cam 'ID (Fig. 2D) until the switch S completes a revolution.

'Ihe clutch magnet TM of the transmitting switch T is then energized from positive, contacts st3, cam TB in position I, clutch magnet 'I'M and relay MS to negative operating TM and MS'.

The transmitting switch T then drives under control of its TA cam, which forms a holding circuit for clutch magnet TM after cam 'I'B leaves position I, until it reaches position I51/2. During this revolution of the transmitting switch, contacts z'sl send a code of impulses over the line LI, L2, the relay IS being operated from positive, contacts st2, the impulsing cam TQ in conjunction with cams TH-TP and certain coding contacts a-q. In this case the contacts by and lc are connected to positive via contacts st2, cam SP with the Searcher switch S in position I, and contacts 2Ilr3. As the transmitting switch revolves, relay IS is operated for along prepare period from TQ, released for two impulses by the impulsing cam TQ, then held operated between positions F1/5% for a long interdigital pause by contacts 'b on cam TH, released for four more impulses from the impulsing cam TQ, held operated for a second interdigital pause by contacts 7c on cam TM between positions 81/4/ IDM; and released for a third digit of seven impulses and nally held operated over cam TP, to which positive is applied in position I411/ I8.

It will be seen, therefore, that the code 241 is transmitted while the transmitting switch T moves into position IBI/2. Y

Relay FPR is then operated from positive, carn TD winding of FPR to negative and the contacts ffm-I, fm2 transfer the line wires LI, L2 to the operating coil of relay RC. Inv order to guard against the possibility of false operation due to code faults, the codes chosen are so arranged that each code consists of three digits adding up to a constant total (13 in this case).

Relay IR, at the receiver, Fig. 2C', operates in response to battery feed from the transmitter circuit energizing RG from positive over tgl and operation of RG operates RGA over contact rgI. Relays RG and RGA are held operated through the entire code.' Relay DC is pre-energized .from positive, rgal, cat to `negative at the beginning of each digit, and after CA operates during each digit, as explained later, DC is held by repeat impulses from contacts IRI via dcaI, caI. DC operates DCA from positive contacts dol winding of DCA to negative.

' During the first digit, DMA is operated from positive rgal,`dca2, hdxl winding of DMA to negative, and locks via dmaZ. Operation of DMA closes a circuit for DMB at dmaI operating DMB. During the second digit DMC and DMD operate, and during the third digit, DME `and DMF as will be described in detail later.

Operation of relay PO closes an energizing circuit for relay POA via irI, deal, poaI, pol, p02, cbl to negative. Operation of relay POA moves its contact poul over preparing a circuit for relay PE. At the end of the impulse POI remains operated in series with POA from positive, rgaI, dma4, winding of POA, pol, pc2, winding of PO to negative.

The second impulse is then routed from positive, z'rI, dcaI poaI winding of relay PE to negative, operating PE and releasing PO and POA at pc2. Relay PE locks over its Contact pel, and release of relay POA returns its contact paal to its original position.

I-t will be seen, therefore, that relay PO is operated by the rst impulse, released by the second,` re-operafted by the third and so on.

'Ihe number of operations of relay PO is counted by the train of counting relays CA-CG.

Positive, rgal, dmad, pc2, cbl, windingof CA operates CA for the rst impulse closing a circuit through winding ofrelay CB at cd2. Relay CB does not operate, however, since its winding is short circuited at p02. The opening of pc2 on the second impulse allows CB to operate in the locking circuit of CA. Similarly the third to the seventh impulses operate CC CG. At the end of the first digit relays DC and DCA release. The last operated counting relay, in the example selected relay CB, in conjunction with relays DMA and DMB, selects a relay in the storage group, HDA, I-IDG, i. e. HDB which operates via rgal, dca2, 'z'r2, cg3, cf2, oe3, cd2, co3, co2, dmbZ to negative, and locks at hdbil in series with I-IDX to rrgaI.

Operation of HDX, releases DMA at hdzrI which in turn releases the operated counting relays CA. Thereafter relay DC is re-operated in readiness for the second digit. Due to the operation of HDX, DMC and DMD are operated instead of DMA, DMB over rgal, dca2, hdI, dma, tnl and dmal, respectively. The second digit is received and stored in a manner similar to the hundreds digit on one of the tens relays, TNA, TNG, in the example TND, which locks at tvLdI in series with TNX. For the third digit DME, DMF are energized since TNX transfers the circuit to relay DME similarly to the transfer after the hundreds digit and remain energized after the digit is received, the third digit being stored on the counting relays themselves.

When relay DC is released at the end of the thirdv digit, one outlet from the receiver is marked,.according to the combination of hundreds, tens and counting relays then operated. If the code 241, for instance, has been received, then the second hundreds relay HDB, the fourth tens relay-TND and' the seventh counting relay CG, would all be operated together with the third digit mark relays DME and DMF.

It will be seen that a circuit is then provided forthe receiving relay 2| DLR connected to the terminal 241 over rgal, z'rZ, cg3, dmc5, kdb-2,'t1zd2 winding` of 2l DLR to negative. In order not to as are used' in 'the particular example are shown in Fig. 2D. 'Ihus only connection to lines corresponding to code numbers 241, 511, 526- and complicate the circuit unduly only such relays 535 are shown. It is clear that similar connections are to be made to the other lines for completion of the system.,

The contacts of the' storage and counting relays are grouped in Such a way that no outlet at all is provided unless the three digits total 13. If the correct code is received and an outlet relay operated, then on the release of relay IR at the end of the codethe winding of relay OK is introduced in Series with the selected receiving relay, mal, dca2, and the rest of the circuit as previously traced and the relay OK consequently operated. This relay sends the check-back impulse vto the transmitter circuit, Figs. 2Av and 2B, by connecting battery feed via ocI, 0162 to line LI, L2.

Thefcheck back impulse sent back to the transmitting point operates relay RC, Fig. 2B. Relay RC locks via rcI and camTD.

Contacts rc3 apply to a positive over cam TB in position l51/2 to re-energizethe transmitting clutch magnet TM in Series with MS and Socause -the switch T to drive home. At the end of every code transmitted, relay FPR is energized in position I51/2 of cam TD and the fault indication lamp FIL will be illuminated over contacts fpr3 for a short period and in the event of the check back impulse not being received the transmitting switch will remain in position ISI/2 andthe fault indication lamp will remain illuminated.

Assuming that the code has been correctly received, 4a circuit will be completed from positive, contacts rc2 (Fig. 2A), cam TE in position I 51/2, vhigh resistance Winding of relay AR, cam SK in position I, winding of relay 2 I LR, resistance 2 IYB to negative.

Relay AR operates on this circuit and locks over contacts arl, cam TF andfcontacts rc2.

The relay ZILR, however, cannot operate in series Vwith the high resistance winding AR., but

-operates when this winding is short circuited by contacts a12 and cam TE.

When relay ZILR operates, it locks over contacts 2 Il1'2 in a local circuit with resistance 2 I YB and thereafter relay 2ILR can only be released by short circuit.

When route 2| is set up, key 2 IRK is in its lower position and relay 2 ILR is energized, so that the 'upper contacts 2IZrl are closed. To break down the route, key ZIRK is returned to normal position, and transmission of code 256 is initiated starting the motor and operating switches S and `T in the Same manner as described in connection with the'transmission of code 241. When switch T reaches position I51/2, relay AR is not operated, since it is short circuited via cam SK and contacts 2 Ilr2. In this case when the transmitting switch moves into position IBM?, positive is applied over contacts rc2, cam TE, contacts arS, cam SG in position I, resistance ZIYB to short circuit the winding of relay ZILR which would therefore release.

It will be seen, therefore, that when the route setting code is sent relay 2ILW will be operated at the end of the code and conversely when the route breakdown code is sent, relay ZILR will be released by short circuit at the end of the code.

WhenY relay 2ILR was operated after transmitting yt'heroute--Setting code 241, the operation of contacts 2IZ1'I released SS and ST and at the same time prepared a circuit for the reoperation of SS as soon as the switch 2 IRK was restored to normal. f

When the switch ZIRK is restored to normal, the cycle of operations just described in connection with operation of the key will be repeated, except that the code ,transmitted will be 256 since the contact of cam TM will be marked instead of contact lc of cam TM, over contacts 2Il1'3. Setting up of connections through code 256 short circuits the winding oi relay ZIDLR positive, ZIdZrI, tne2, hdb'3, dme, ef2, eg3, irl', dca2, rgal, to positive, causing it to release.

It should be noted that the code transmitted and the LR relay operated have been associated with route 2| by virtue of the fact that the Searcher switch S was standing in position I, one position of the Searcher switch being allocated to each route.

In addition to the route control switches, the panel iS equipped with a number of individual switch point control switches. These Switches are capable of taking up one of three positions, normal-'which attempts to set the switch points to normal, reverse-Which attempts to set the switch `points to reverse, and central-which leaves the switch points free to be operated either normal or reverse, as required by the setting of the route switches.

On th-e transmitter circuit the switch point control switches are Shown in two parts, for example,

' GIPKN, BIPKR. 'The switches are shown in the central position: if operated to the normal position then the portion IPKN will be operated and if operated to the reverse then BIPKR will be operated.

Oneposition on the Searcher switch S is allocated to the normal position of the key and one t'o the reverse position and, furthermore, NLR and RLR relays are provided associated with the two positions of the control switch.

The method of positioning the Searcher switch and transmitting the code is similar to that described for the route switch except for the following points, and ltherefore need not be traced 4in detail.

Since it is impossible for a switch point control yswitch to occupy the normal and reverse positions at the Same time because of its construction, the transmission of, say, the-normal code, renders it superfluous to transmit in addition a central code in the event of the switch having ybeen operated right over from reverse to normal without stopping in the central position. Contact BInZrS is therefore included in the locking vcircuit for relay tIRLR and contacts 6Irlr2 in the locking circuit for NLR. Furthermore, the same code (5I1) ycan be used to indicate that the switch point control switch is restoredl to its normal position, independent of whether it was operated from normal (in which caser the Searcher switch will be in position II with relay GINLR operated) or from reverse (in which case the Searcher switch will be in position I2 with relay GIRLR operated).

In the event of any fault occurring in the transmission or reception of the code, the check back signal will not arrive and the transmitting switch will remain in position I51/2 with the fault lamp illuminated, as explained above in connection With the route setting Switch. 'I'he signalman must then operate the fault clearing key FK (Fig. 2B) which operates the slow release relays CFG over an obvious circuit. On the release of the fault key, relay CF will be operated over contacts cfgl and cam TG in position I51/2.

Relay CF locks over contact cfl and cam TD, and, contacts cf2 energize the clutch magnety TM, positive, cf2, cam TB, magnet TM, relay MS to negative to drive the switch T home.

Since the switch returns home without relay RC operated, no operation or release of the LR relay corresponding to the operated key will be effected.

If the panel key which originated the code has lnot been restored, then a circuit will still be available for relay ST when the transmitting switch reaches its home position and therefore the transmitting switch will commence a second revolution and re-transmit the same code.

'I'he circuits completed by the outlets from the code` receiver are utilized to operate certain route selecting or switch point operating relays. For example, a relay ZIDLR will be operated when positive is applied by the code receiver, as explained above, to the terminal 241.

When operated, relay ZIDLR will lock over a second winding and ZIdZrrI in series with a resistance and from this condition can only be released when a further positive is applied by the code receiver to the terminal 256.

It will be seen on reference to the transmitter circuit that the code 241 is transmitted. when the panel switch for route 2l is reversed and code 256 is transmitted when the same switch is restored to normal. It is apparent, therefore, that relay ZIDLR, adjacent the switch points and signal, follows the operation of the corresponding panel switch.

Similarly two switch point control relays 6 INDLR and 6 IRDLR follow the operation of the individual panel switch for controlling switch points 6I. The operation of the panel switch` 6I tonormal will transmit code 526 as explainedpreviously and subsequently operate GINDLR which locks over GImZrI, while the operation of the panel switch to reverse, transmits code 535 and operates relay SIRDLR which locks over Slrdlrl. The code 5I`| transmitted when the panel switch is restored to its central position either from normal or from reverse, will effectively short. circuit the holding windings of both relays BINDLR and BIRDLR, and when both these relaysfare deenergized, switch points will be free for operation to set up a route in accordance with the operation of a route panel key.

In the event of the switch point control switch being operated from normal to reverse Without pausing in the central position, the operation of the reverse switch point control relay BIRDLR disconnects the holding circuit for the relay GINDLR at 6 Irdlr2 since it is obviously inadmissible that the normal and reverse switch point control relays should be operated at ther same time.

Since it has been shown that relays adjacent the switch points and signals repeat the operation of all route and switch point control switches on the panel, the local interlocking necessary between such routes and points may be provided by means of an interlocking system using sequence switches or wiper switches as described in application Ser. No. 209,198. The principles of this type of interlocking.are fully described in this application No. 209,198 and therefore no description of tlre interlocking arrangements is given. in this specification.

Remote indication of points, signals and tracks The system used for indicating back to the control panel the state of switch points, signals and tracks, is similar in principle to that described. in British Patent No. 461,136 and preferably uses a signal channel independentl of that used for control codes, although it is possible for the channel normally used for indication purposes to be switched over to carry out the control functions if required.

British Patent 461,136 referred primarily, though not exclusively, to centralised indication of the con-dition. of a number of track relays spaced at intervals along the track, the signal channel being fed` through all such locations in turn.

In the example now described, it is assumed that there are a number ofA individual track` locations of this type, together with a number of devices concentrated at one point as, for example, in the interlocking area described above.

Figs. 3A and 3B arranged one above the other show the control station equipment at IE Fig. 1, while Figs. 3Cv and 3D show a typical isolated wayv station WS,` GWS of Fig. l, such as may be used for repeating thecondition of a track relay to the control room and also the manner in which the way-station equipment may be modified when a number of functions to be indicated are concentrated at one point and for' showing the connection of the circuit should be arranged, in order, to the right of Fig. 3A.

The operation ofv this circuit is briefly as follows:

At the right hand side of` Figs. 3A and-` 3B is shown a series of typical contacts from one level of a continuously motor driven distributor, the moving. arm of which is connected to line LNI. When the moving arm passes over the first contact of the distributor,. current is fed from the positive pole of battery MB, line L2, track contacts trI if the corresponding track section 361/363 is clear, rectifier RA, oal,y line LNI' at the rst track position line LNI, the flrst wiper contact` Winding` of. relay 36 I /3U3MR tonegative pole of battery If track /303 isclear at this instant, the relay`30I/303MR will be operated and will lock itself through lock cam CAM C.

When the distributor arm moves on to the second contact, the poles of reverse current from the auxiliary battery AB will. be fed over the line. This vvllpass through rectifier RC and the relay P at the first track location. Relay P operates independently of the condition of the track relay and operates relay O from a small local battery t, contact'. pI, closing contact o1. Relay OA however, does not operate asA it is short circuited; at pI.

When the` distributor arm moves off this contact', relay P is released and' relay OA thereupon operatesin series with relay O, t, winding of OA, oI", acaI, winding' of O, Contactsoal transfer l'ineLNI' from track section 361/363" tothe succeedingy track section 312 where a similar cycle of operations is completed and the relay 312MB.'

' battery.

'2I/22MR at the control station, contacts OAI,

rectier CRA at the way-station, back contacts of all CR relays, contacts 2Ihr3 and 22h73 (provided that neither of these signals 2| and 22 has been cleared) and back over line NL2 to the main It will be seen, therefore, that relay 2I/22MR operates if the signals 2| 22 are at danger.

The next stepping impulse isrouted over an obvious circuit through rectifier CRC and relay CP operating CP regardless of the track condition. CP operates relay CO, cacaI, cpl, coaI, winding of CO, relay CP is released and COA operates in series with CO, winding COA, cpeZ, COI, winding CO,

It should be noted that all the local switching at the remote station is controlled by a positive fed over contacts cacal.

'Ihe second operation of CP will cause relay CPE to be operated off contacts coaI and contacts cpe2 thereupon release relays CO and COA. It will be seen, therefore, that relay CO is operated by the rst stepping impulse, released by the second, re-operated by the third, and so on.

The rst operation of CO causes relay 2 I /22CR to operate t, CO2, back contactsof relay 23 /24CR, winding of 2I/22CR, On the release of CO krelay 23/24CR comes up in series with 2 I/22CR. The next operation of CO causes relay 25/26CR to operate and so on through CR relays associated with all the signals, vpoints and track relays in the remote controlled area. The second testing impulse, which is fed through relay 23/24MR in the control station arrives after the iirst stepping impulse and is fed through rectifier CRA, back contacts of all CR relays up to 23/24CR and front contacts of '2I/22CR through contacts 23/24h13, provided that the signal 23/24 is at danger.

As successive stepping impulses operate the various CR relays, so the testing impulses will Abe fed rst through contacts of the HR relays to the state of all signals, points and tracks.

If every testing impulse from the distributor has been eiective in stepping the line from waystation to way-station and thereafter in operating all the CR relays correctly, then when the distributor arrives at the point connected to the -relay SYN, the relay 208CR at the remote station should be operated and the relay SCR should not be operated since 208CR short circuits SCR. In this condition a synchronising battery situated at the remote station will be connected 4from the rectifier CRA to operate the relay SYN.

If an insucient number of impulses have been effective, then relay 208CR will not be operated so the circuit will not be established. Alternatively if too many stepping impulses have been received, then relay SCR will also be operated, breaking the circuit for SYN, so that the operation of the relay SYN is a definite proof that all the way-station equipment has correctly responded to the stepping impulses. This means that the group of MR relays which has been operated can 2l/22RKE 29/30DKE,

be accepted as a reliableindication of the state of all signals, point and track relays.

When relay SYN is operated it also locks to CAM C and thereafter cam CAM A is operated by-the distributor, so thatthe setting of the MR relays is transferred toa corresponding group of DR relays over CAM A, syn2,the various lmr contacts and windings of the DR relays, the operated DR relays locking themselves over their front contacts and cam CAM B.

CAM D thereupon opens itsv contacts, breaking the locking circuit for any DR relays which were operated previously and are not required to be re-operated. -Y Y CAM B then recloses to restore the locking circuit for the new set of DR relays and thereafter CAM A re-opens. CAM C is then opened to unlock al1 MR relays, leaving them ready for re-operation in the succeeding cycle.

CAM D then connects the main battery between lines LN2 and LN3, thereby operating the ACA relay at the first track location. ACA unlocks O and OA at acal and the release of relay O transfers at O2 the clearing impulse to the second track location where another ACA relay will be operated. In this way ACA relays at all stations are operated in turn, restoring the waystation equipment to normal. In the case of the remote controlled station the relay CACA is operated, removing the main positive to all counting relays etc., sothat they are all released in vreadiness for the next cycle.

The DR relays at the control station control the illumination of all signal indication, point detection and track indication lamps on the control panel at their dr2 contacts so that at the end of every cycle of the distributor the complete indication as shownby the control panel,A is brought into line with the remoteequipment.

As shown,the track indication relays operated for track sections at each way-station'control twin lamps 30I/303TKE 302TR'Which are` illuminated when the track is occupied, i.A e. When the DR relay is de-energized. A positive proof that a track section is clear is required'to operate relay DR and extinguish the indication lamps. In the case of signal indications lamps 2 I /22DKE,

29/30RKE corresponding to the positions of keys ZIRK 3IIRK of Fig. 2A, a green lamp is illuminated 'when the relay DR is de-energised and it is lnecessary to receive a positive signalA before the vrelay will be operated, to show that the signal has been placed at danger.

In the case of the point detection indicators, separate relays are provided, for instance, 6 INDR and 6 IRDR, etc. corresponding to 6 IPKN, 6 IPKR,

fetc. Fig. 2A, each relay controlling, for example,

two -lamps BINKE, EIRKE, etc., one at each end of the point switch on the diagram. -In the event of points being in an intermediate position, no

.point detection would be indicated.

.In the remote indication system described above, a three-Wire channel throughout the waystations has been assumed, the third wire being used as described for clearing down way-station equipment after a test.

,Itl will be clear, however, that the alternative two-Wire methods, as described in British Patent No. 461,136 are equally applicable.

It is possible that the remote vcontrol of a sequence switch interlocking system could be effected by various coding methods other than that described above, and, furthermore, that the indication back to the control panel could be carried out by several known methods as, for

example, a coding system in which any change in way-station apparatus originates a unique code which is transmitted back to the control station, where it actuates a receiver to make the necessary change to the control diagram.

The remote indication cycle is continuously repeated so that there is a constantly repeated check or the condition or position of every device which is being supervised.

What is claimed is:

1. A system for remote control of railway signals and switch points, for setting up a selected route over a given track layout by operation of 15 track switches and signals, comprising control panel equipment at a distant point from said signals and switch points comprising independently operable manually adjustable route selecting means, route setting equipment normally responsive to operation of said route selecting means located adjacent said track layout to control the setting of the switches and signals in accordance with a selected route to be set up, said route setting equipment incorporating means providing electrical interlocking between conflicting routes, a transmission channel for transmitting a control signal comprising energy impulses, between said route setting equipment and said control panel equipment at said distant point, signal transmitting equip-ment at said distant point controlled by adjustment of said independent route selecting equipment for applying control signal impulses to said line corresponding to the selected route, signal receiving equipment at 35 said route setting equipment position responsive to received signal control impulses transmitted over said line, means in said route setting equipment responsive to said received signals for operating said route setting equipment to set up a 40 selected route corresponding to every operation of said independent route selecting means, remote supervisory equipment comprising condition-signaling equipment adjacent the track equipment controlled by said route setting equip- 45 ment in response to the condition of said signals and switch points, indicating equipment at the distant point arranged to receive via a signal channel indications of the condition of said route setting equipment, and means for providing a 50 continuously repeated cycle of indications of the condition of all the signals and switch points, said remote supervisory equipment also including way-station condition-signaling equipment individual to each track section of a length of 55 track, whereby the indicating equipment at the distant point gives information concerning the condition and setting of a length of track including the said remotely controlled set of signals and switch points.

2. A railway signal and points control system as claimed in claim 1 in which said way-stations are arranged first to transmit condition signals to the signal cabin and then to switch through the signal channel to a succeeding way-station, 65 the way-station for said remotely-controlled set of signals and points being arranged to transmit a succession of condition signals giving information of the condition of all the signals and switch points before switching the channel through to 70 succeeding way-stations.

3. A system for the remote control of railway signals and switch points, comprising control equipment at a control station, a plurality of route keys independently operable for initiating 75, transmission of selected route setting signals,

means responsive to operation of a route key for transmitting a selected route setting code signal dependent upon the key operated, receiving means forreceiving said code signal responsive to receipt of said code for setting up the selected route corresponding to said received code signal, and means at said receiver for blocking the setting up of said selected route in event it conflicts with another route previously set up.

4. A system according to claim 3, further comprising means at said control station responsive to impulses initiated by blocking of said selected route 'for indicating this condition, and means for indicating said signal and restoring said receiver to condition for setting up another route.

5. A system for remote control of railway signals and switch points, for setting up a selected route over a given track layout by operation of track switches and signals, comprising control i panel equipment at a distant point from said signals and switch points comprising independently operable manually adjustable route selecting means, route setting equipment normally responsive tov operation of said route selecting means located adjacent said track layout to control the setting of switches and signals in accordance with a selected route to be set up, said route setting equipment incorporating means providing electrical interlocking between conflicting routes, a transmission channel for transmitting a control signal comprising energy impulses between said route setting equipment and said control panel equipment at said distant point, signal transmitting equipment at said distant point controlled by adjusment of said independent route selecting equipment for applying control signal impulses to said line corresponding to the selected route, signal receiving equipment at said route setting equipment position responsive to received signal control impulses transmitted over said line, means responsive to said received code signals for operating said route setting equipment to set up a selected route corresponding to every operation of said independent route selecting means, remote supervisory equipment comprising condition-signaling equipment adjacent the track equipment controlled by said route setting equipment in response to the condition of said signals and switch points, indicating equipment at the distant point arranged to receive indications of the conditions of all of said signals and switch points, a signal channel interconnecting said indicating equipment and said condition-signaling equipment, and means for continuously repeating a cycle of said indications from said supervisory equipment to said indicating equipment.

6. A system for remote control of railway signals and switch points, for setting up a selected route over a given track layout by operation of track switches and signals, comprising control panel equipment at a distant point from said signals and switch points comprising independently operable manually adjustable route selecting means, route setting equipment normally responsive to operation of said route selecting means located adjacent said track layout to control the setting of the switches and signals in accordance with a selected route to be set up, said routesetting equipment incorporating means providing electrical interlocking between conicting routes, a transmission channel for transmitting a control signal comprising energy impulses between said route setting equipment and said control panel equipment at said distant point, signal transmitting equipment at said distant point con- 10 tion responsive to received signal control impulses transmitted over said line, comprising means 1e sponsive to reception of all ofsaid code signal impulses to transmit back to the signal transmitting station a signal indicating the correct reception of said code signal, means responsive to correct reception of said received code signals for operating said route setting equipment to set up a selected route corresponding to every operation of said independent route selecting means.

JOHN BALMAIN GRIFFITHS. 

